Carburizing box with centrifugally cast side walls



Nov. 30, 1937.

H. H. HARRIS CARBURIZING BOX WITH CENTRIFUGALLY CAST SIDE WALLS Original Filed May 17, 1935 INVENTOR Henry H. Harris ATTORNEYS Patented Nov. 30, 1937 UNETED STATES CARBURIZING BOX WITH CENTRIFUGALLY CAST SIDE VVALLS Henry H. Harris, Champaign, Ill.

Original application May 17, 1935, Serial No.

Divided and this application March 30, 1936, Serial No. 71,577

2 Claims.

The present invention relates .to carburizing boxes, and particularly to carburizing boxes: with centrifugally cast side walls. The present application is a division of my copending application, Serial No. 21,926, filed on May 17, 1935.

The main object of my invention is the provision of a centrifugally cast side walls member for carburizing boxes which is highly dense and substantially free from porosity.

Another object of my invention consists in the provision of a centrifugally cast side-walls member for carburizing boxes comprising a continuous integral tube.

A further object of my invention consists in the provision of a centrifugally cast side Walls member for carburizing boxes comprising a continuous integral tube free from joints at the corners, polygonally sectioned, preferably rectangular in Shape.

Another object of my invention consists in the provision of a centrifugally cast tubular member, cut off lengths of which may be formed into side-walls members for carburizing boxes, with extra material added to form thickened parts constituting elemental or longitudinal parts of the completed tubular member, and which constitute reinforcements for strengthening the box at the corners.

A further object of my invention is the provision of a carburizing box the side walls member of which is centrifugally cast and the end or head portion of which is welded thereto to complete the box.

Other objects will appear from the following description of certain illustrative embodiments of the invention shown in the accompanying drawing, in which Fig. 1 is a cross-sectional view of a centrifugally cast tubular body, lengths of which may be cut off to form side walls of a round carburizing box;

Fig. 2 is a similar view of a modified form of centrifugally cast tubular body deformed into substantially rectangular shape and provided With extra reinforcing material at the corners;

Fig. 3 is a section of the tube of Fig. 2 flattened in parts to form side walls of a substantially rectangular box;

Fig. 4 is a Vertical sectional view of a carburizing box having centrifugally cast side walls and with an end or head member welded in place, the box being shown set in a tray and containing carburizing compound and parts to be carburized, and

Fig. 5 is a view similar to a portion of Fig. 4, showing a modified form of end or head.

Reference character JO designates a centrifugally-cast round tubular member which, by being cast in a rotating mold, is subjected in molten 5 state to centrifugal force whereby it is made dense and resistant to carbon penetration. The metal used is of the alloy type adapted to stand up' well under the conditions encountered in carburizing work at high temperatures. An allo'y metal of nickel-chromium-iron composition, for example, is well adapted for such purpose, and the dense, close texture which is obtained by centrifugal casting enables longer useful carburizing box life to be obtained with given proportions of the alloying metals, such as nickel and chromium, than when casting in the ordinary way with the identical composition. When the side-walls member for the carburizing box is to be round,V the centrifugally cast tube IO for providing such side walls may be of uniform thickness, as shown in Fig. V1.

In a modification, I may provide such a centrifugally cast tubular member Ifla as shown in Fig. 2, with lengthwise extending thickened portions |2, 12. In Fig. 2, I have shown four such thickened portions |2, arranged in pairs, and by flattening the longer intermediate portions Ill, 14, to form substantially flat sides 16, and fiattening out the shorter intermediate portions |8, Ii!V to form substantially flat ends 20, 20 of a side walls member 22 shown in Fig. 3, a thickened wall part and strengthening effect is obtained at the corners, indicated at |2b, |2b. The wall flattening may either be performed on an elongated tube and the tube thereafter cut into lengths to form the side walls member for carburizing boxes of approximately the length indicated at 24, Fig. 4, or the centrifugally cast tubular member may first be cut into lengths, or Originally made in lengths suitable for box wallsV and then side-flattened, the metal being raised to a suficiently high temperature, though well below the melting point, to permit the operation of flattening out the sides to be performed without cracking or breakage at the Corners or elsewhere.

The ends or head members may be made in Various ways. Rolled or sheet-material may be i used if desired, or cast heads 26 of metal similar to that used for the side Walls may be provided, and same can be welded into place to close one end of the box. In the form shown in Fig. 4 the cast head 26 comprises side walls or flanges 28 of substantially the same diameter as the sideV wall members and forming substantially continuations of said side Walls of the box when Weided thereto as indicated at Si). In Fig. 5, the head 25a is made som-ewhat larger so that the side Wall ange 28a, thereof encompasses the side Wall member of the box and same are Welded together interiorly and exterior'ly at 313 and 3G respeotively, but in each case the sha'pe of the head member is identical With that of the side Wails portion.

For use, the boxes with oiosed end 2G down are usually loaded With pieoes 38 to be carburized and carburizing compound the tray G2 set on top, and the whole then inverted into the position shown in Fg. 4. The heads 25a, may be provided with feet M, la if desired.

Further modifications within the scope of my claims are included Within my invention.

Having described my invention what I ciam and desire to secure by Letters Patent is:

l. A carburizing box comprising a many-sided centrfugally cast hollow prism forming the side Walls portion of said box, said sides being substantialiy fiat and having substantially integral thiekened parts extending lengthwise thereof at the outside defining Corners of the box and having a head member of similar Shape welded thereto ;for closing an end thereof.

2. A carburizing box comprising a centrifugally cast integral side walls member With substantially thiflkened parts on the outside defining corners of the box from the top to the bottom thereof, the portions between the Corners being sub'- stantially fiat, having a simiiarly shaped head member Welded thereto at and closing one end of the side Walls member, said head portion being thickened at the Corners to correpond with the thiokenings en the side Walls member.

HENRY H. HARRIS. 

